For at least the first, uncrewed flight in 2018, NASA will use an interim upper stage.But Congress has been pressing the agency to settle on a new, permanent upper stage, dubbed the "Exploration Upper Stage," in time for the second launch of the SLS rocket in 2022 or 2023.

Disney posted a video today of BB-8 visiting the NASA Jet Propulsion laboratory to meet Maggie, a Mars rover.Curiosity photographs the terrain on Mars, surveying the landscape to find out if it was ever capable of sustaining life.